Chlorphenesin

Also known as 3-(4-Chlorophenoxy)-1,2-propanediol, 3-(p-Chlorophenoxy)propane-1,2-diol, 4-Chlorophenyl glyceryl ether, Maolate

Chlorphenesin (3-(4-chlorophenoxy)-1,2-propanediol; CAS 104-29-0; C9H11ClO3) is a synthetic biocide used in cosmetic formulations as a preservative and preservative booster. It is structurally a chlorinated phenoxy glyceryl ether with broad-spectrum antimicrobial activity against bacteria, yeasts, and molds. It is commonly paired with phenoxyethanol and organic-acid preservatives to enhance antimicrobial efficacy and enable lower total preservative loads. The Cosmetic Ingredient Review Expert Panel assessed chlorphenesin and concluded it is safe in the present practices of use and concentration (Johnson, Bergfeld, Belsito et al., Safety Assessment of Chlorphenesin as Used in Cosmetics, Int J Toxicol 33(2):5-15, 2014, PMID 24861369; CIR Final Report September 2012). The Panel reported typical use concentrations of up to 0.32% in rinse-off products and up to 0.3% in leave-on products. The Panel noted that chlorphenesin is well absorbed when applied to the skin of rats; this dermal absorption was a considered point in the assessment but was judged not to raise safety concerns given the absence of systemic toxicity in the available animal data, the low typical use concentrations, and the absence of genotoxicity, reproductive toxicity, or irritation/sensitization signals at cosmetic-relevant levels. The QRT row carries no conditions or concentration limits. Chlorphenesin is unrelated to chlorphenamine (an antihistamine) and chlorhexidine (a disinfectant) despite the similar-sounding names — it is a chemically distinct preservative.